Preparation method of antifibrillated cellulose fiber

Abstract

The invention relates to a preparation method of an antifibrillated cellulose fiber, which comprises the following steps: mixing polyaspartic acid and water according to a mass ratio of 1: (1.5-32) to prepare a finishing liquid, controlling the pH value of the finishing liquid at 7-11, dipping cellulose into the finishing liquid, carrying out a cross-linking reaction at 30-70 DEG C for 0.1-12 hours, washing with water, and drying to obtain the antifibrillated cellulose fiber, wherein the mass of the cellulose is 1-70% of the mass of the polyaspartic acid. The preparation method comprises the following steps: dissolving cellulose in an aqueous solution of N-methylmorpholine-N-oxide, drying at 40-80 DEG C to obtain crosslinked cellulose, stirring and dissolving the crosslinked cellulose and the aqueous solution of N-methylmorpholine-N-oxide in a reaction kettle at 90-110 DEG C under a vacuum condition for 3-5 hours to prepare a uniform and transparent spinning solution with the mass fraction of 6-10%, and spinning to prepare the fibrillated fiber. The method has the advantages of being simple in process, more environmentally friendly and good in antifibrillation effect.

Description

Technical Field

[0001] The present invention relates to a method for preparing antigen fibrillated cellulose fibers. Background Art

[0002] As an important textile raw material, cellulose fibers have the advantages of good wearing comfort, hygiene and health, complete degradability of waste products, and no white pollution, and are the mainstream raw materials in textiles. Natural cellulose fibers mainly refer to products such as cotton and hemp, but their output is limited and it is difficult to meet the consumption demand of textiles. Therefore, regenerated cellulose fibers have been developed, mainly using natural substances such as cotton linter, wood, bamboo, and straw, extracting the cellulose components therein through certain methods, and obtaining cellulose fibers through the reshaping of the spinning process. Such cellulose fibers have stable quality and performance, are hygienic and healthy, and the waste products can be completely degraded without white pollution, effectively meeting the market demand for cellulose fibers.

[0003] Fibrillation is a process in which fibers are rubbed against objects such as fibers or metals in a wet state. Due to the action of fiber swelling and mechanical tension, the fibrils are longitudinally peeled off along the main body of the fiber to become macrofibrils with a diameter less than 1 - 4 micrometers, and then split into finer microfibrils. Among all regenerated cellulose fibers, Lyocell fibers have the highest fibrillation grade. Fibers without fibrillation treatment are prone to problems such as a "dull" appearance, poor aesthetics, poor washability, uneven dyeing, etc. in the subsequent dyeing and finishing process, and are prone to pilling and fuzzing during fabric wearing. Therefore, it is of practical significance to perform anti-fibrillation treatment on fibers to improve their application performance. In order to prevent or reduce the occurrence of cellulose fiber fibrillation and improve its anti-fibrillation performance, there are many methods for reducing or removing fibrillation throughout the development process from cellulose fiber spinning to fabric, such as adjusting spinning process parameters such as the speed of the spinning solution flowing through the spinneret, the diameter of the spinneret orifice, the width of the air gap, the temperature and humidity of the air flow, and controlling the wet processing time during production to reduce tension and friction to change the fibrillation grade and properties of cellulose fibers. However, the method of reducing fibrillation by changing process parameters cannot fundamentally solve the problem of fibrillation. Currently, the more commonly used method for anti-fibrillation treatment of cellulose fibers is the chemical cross-linking method, that is, during or after spinning, a suitable cross-linking agent is used to react with cellulose or cellulose fibers to form a bridge between cellulose molecular chains, forming a network cross-linking structure system composed of fibers and cross-linking agents, so as to essentially avoid the generation of fibrillation.

[0004] For example, in the Chinese invention patent with the application publication number CN114232120A and the title "An antigen fibrillated cellulose fiber and its preparation method", a preparation method of an antigen fibrillated cellulose fiber is disclosed, which includes the following steps: (1) adding a crosslinking agent tannic acid to the cellulose fiber spinning dope according to a weight ratio to prepare a spinning solution; (2) spinning the spinning solution prepared in step (1) by wet spinning or dry-jet wet spinning, and coagulating it in a coagulation bath to obtain a nascent fiber containing a crosslinked network of five-membered ring chelates and a hydrogen bond crosslinked network structure, and then washing and drying it to prepare the antigen fibrillated cellulose fiber. Adding a crosslinking agent to the spinning solution increases the difficulty of process control of the spinning and increases the instability.

[0005] Again, the authorized announcement number CN110172754B, with the title "A preparation method of an antigen fibrillated cellulose-based fiber", discloses a preparation method of an antigen fibrillated cellulose-based fiber. The cellulose-based fiber spinning solution is extruded through a spinneret, coagulated, stretched and washed to obtain washed silk, and then the washed silk is treated with an aqueous crosslinking agent solution, followed by rinsing and drying to obtain the antigen fibrillated cellulose-based fiber; the temperature of the washing is ≥90 °C, and the termination condition of the washing is that the water content of the washed silk is 40-70 wt%; the temperature of the aqueous crosslinking agent solution during treatment is 65-90 °C, and the temperature of the rinsing is 20-40 °C; the crosslinking agent contains one or more of X group, Y group and Z group, the X group is an aldehyde group, a cyano group, an epoxy group, an acyl chloride group, an acid anhydride or a diisocyanate; the Y group is a siloxane; the Z group is a sulfonic acid group or a sulfate group. The above crosslinking agent uses substances such as aldehydes, which cause relatively large environmental pollution and relatively difficult treatment, making the industrial production of antigen fibrillated cellulose fibers more difficult.

[0006] Based on the above problems, the applicant has studied the above problems and produced this case. Summary of the Invention

[0007] The purpose of the present invention is to provide a preparation method of cellulose fibers with simple process, better environmental protection and good antigen fibrillating effect.

[0008] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0009] A method for preparing antigen fibrillated cellulose fibers is carried out in the following manner: Polyaspartic acid and water are mixed at a mass ratio of 1:1.5 - 32 to prepare a finishing solution, and the pH of the finishing solution is controlled at 7 - 11. The cellulose is impregnated in the finishing solution, and the mass of the cellulose is 1 - 70% of the mass of the polyaspartic acid. A cross-linking reaction is carried out at 30 - 70 °C for 0.1 - 12 h. After washing with water, it is dried at 40 - 80 °C to obtain cross-linked cellulose. The cross-linked cellulose and an N-methylmorpholine-N-oxide aqueous solution are stirred and dissolved in a reaction kettle under vacuum conditions at 90 - 110 °C for 3 - 5 h to prepare a uniform and transparent spinning solution with a cross-linked cellulose mass fraction of 6 - 10%. Through spinning, antigen fibrillated fibers are prepared.

[0010] As a preferred embodiment of the present invention, after the cellulose is impregnated in the finishing solution, ultrasonic treatment is carried out for 12 - 18 min.

[0011] As a preferred embodiment of the present invention, the mass percentage of N-methylmorpholine-N-oxide in the N-methylmorpholine-N-oxide aqueous solution is 85 - 88%.

[0012] As a preferred embodiment of the present invention, dry-jet wet spinning is used for spinning, and after coagulation in a coagulation bath, washing with water, and drying, antigen fibrillated fibers are obtained, wherein the coagulation bath uses an aqueous solution of an N-methylmorpholine-N-oxide aqueous solution with a mass fraction of 15 - 20%.

[0013] As a preferred embodiment of the present invention, the pH value of the finishing solution is adjusted by sodium hydroxide.

[0014] As a preferred embodiment of the present invention, the molecular weight of the polyaspartic acid is 1000 - 5000 Da.

[0015] As a preferred embodiment of the present invention, the cellulose is bagasse cellulose or poplar wood cellulose.

[0016] After adopting the technical solution of the present invention, polyaspartic acid is used to modify Lyocell fibers. With polyaspartic acid as the cross-linking agent, by controlling the mass ratio between Lyocell fibers and polyaspartic acid, cross-linking reaction conditions, etc., the cross-linking degree of the cross-linking network is controlled, and the fibrillation resistance effect is obvious, meeting the requirements of actual processing and application. The cross-linking conditions (cross-linking time, pH value of the finishing solution) and the mass ratio between cellulose fibers and polyaspartic acid will affect the fibrillation resistance effect of cellulose fibers. When the cross-linking time is short or the mass ratio of cellulose fibers to polyaspartic acid is low, only a small amount of polyaspartic acid will adhere to the surface of cellulose fibers, and the enhancement effect of the binding force between the fibrils of cellulose fibers is not obvious, resulting in a poor fibrillation resistance effect; when the cross-linking time is too long or the mass ratio of the cross-linking agent is high, more polyaspartic acid adheres to the surface of cellulose fibers, and the hydrogen bond interaction between the outer-layer adhered cross-linking agent and cellulose fibers is small and is relatively easy to fall off, causing waste of the cross-linking agent. Therefore, by selecting an appropriate cross-linking time and the mass ratio between cellulose fibers and polyaspartic acid, not only can the cellulose fibers achieve a better cross-linking effect, but also the consumption of polyaspartic acid can be reduced, thereby achieving the fibrillation resistance effect at a lower cost. The slightly alkaline finishing solution has an etching effect on the fibril fluff peeled off from the surface of the main fiber and is easy to remove the fluff; in addition, the molecular volume of the slightly alkaline finishing solution is larger than that of water molecules, which can effectively isolate cellulose molecules and form a hard and dense surface layer on the surface of cellulose fibers, making it difficult for fibrils to peel off from the main fiber, playing a role in cross-linking and fibrillation resistance.

[0017] The polyaspartic acid cross-linked Lyocell fiber technology provided by the present invention has simple and easy steps. The formaldehyde-free cross-linking agent polyaspartic acid used is non-toxic and does not pollute the environment. During production, storage, and the use of the fibers or fabrics treated with it, formaldehyde compounds will not be released, with high durability and no chlorine absorption, chlorine loss, and yellowing phenomena. Lyocell fibers are composed of aggregates (macro fibrils or micro fibrils) formed by highly oriented and highly crystalline cellulose molecules arranged parallel along the longitudinal direction, and the fibrils are connected by adjacent non-oriented cellulose molecules to form an amorphous region. The binding force between the fibrils in this amorphous region is the hydrogen bond interaction between the hydroxyl groups on cellulose in the fibrils, and the binding force is weak. By impregnating in a finishing solution containing polyaspartic acid, polyaspartic acid enters the amorphous region of cellulose fibers, and a stable hydrogen bond interaction is formed between the peptide bonds on the polyaspartic acid molecular chain and the hydroxyl groups on the amorphous region cellulose fibers, increasing the binding force between cellulose fibers, thereby reducing the possibility of fibril splitting on the fibers and improving the fibrillation resistance ability of the fibers. Detailed implementation manners

[0018] To better understand the technical solution of the present invention, it will be described in more detail below in combination with embodiments.

[0019] Embodiment

[0020] Prepare a finishing solution containing polyaspartic acid. Dissolve 10 g of polyaspartic acid with a molecular weight of 2000 Da in 50 mL of water with a pH of 10 (adjusted with NaOH) to obtain a finishing solution containing polyaspartic acid.

[0021] Immerse 0.2 g, 1 g, 2 g, and 5 g of bagasse cellulose (the mass of bagasse cellulose is measured at 50%, 20%, 10%, and 2% of the mass of the crosslinking agent polyaspartic acid) in the above finishing solution respectively, and sonicate 3 times for 5 min each time to remove the gas in the fiber and make the finishing solution fully contact and react with the cellulose. Carry out crosslinking reaction at 50 °C in an oven for 20 min. After impregnation, wash with water and dry in a 50 °C forced-air drying oven to obtain crosslinked bagasse cellulose. Dissolve 3 g of the above-obtained crosslinked bagasse cellulose and 47 g of an 85% NMMO aqueous solution in a reaction kettle under vacuum conditions at 90 °C with stirring for 3 h to prepare a homogeneous and transparent spinning solution with a mass fraction of 6%. Use dry-jet wet spinning, coagulate in a coagulation bath (an aqueous solution of 15% NMMO, coagulation bath temperature is 20 °C), wash with water (pure water at 80 °C, washing time is 2 h), apply oil (oil bath solution concentration is 2 g / L, temperature is 70 °C, time is 4 h, oil bath model: HY-101, produced by Hangzhou Huaya Chemical Co., Ltd.), and dry (temperature is 60 °C, 24 h) to prepare antigen fibrillated Lyocell fibers. The performance indicators are shown in the following table.

[0022]

[0023] Comparative Example

[0024] Weigh 3 g of bagasse cellulose and 47 g of an 85% NMMO aqueous solution, and stir and dissolve them in a reaction kettle under vacuum conditions at 90 °C for 3 h to prepare a homogeneous and transparent spinning solution with a mass fraction of 6%. Use dry-jet wet spinning, coagulate in a coagulation bath (an aqueous solution of 15% NMMO, coagulation bath temperature is 20 °C), wash with water (pure water at 80 °C, washing time is 2 h), apply oil (oil bath solution concentration is 2 g / L, temperature is 70 °C, time is 4 h, oil bath model: HY-101, produced by Hangzhou Huaya Chemical Co., Ltd.), and dry (temperature is 60 °C, 24 h) to obtain Lyocell fibers with a dry breaking strength of 3.0 cN / dtex, a wet breaking strength of 2.6 cN / dtex, and an elongation at break of 6.97%.

[0025] The protection scope of the present invention is not limited to this embodiment. Any similar transformation made by anyone is regarded as not departing from the protection scope of the present invention.

Claims

1. A method for preparing antigen - fibrillated cellulose fibers, characterized in that, It is prepared in the following manner: Polyaspartic acid and water are mixed in a mass ratio of 1:1.5 - 32 to prepare a finishing solution, the pH of the finishing solution is controlled at 7 - 11, cellulose is impregnated in the finishing solution, the mass of cellulose is 1 - 70% of the mass of polyaspartic acid, cross-linking reaction is carried out at 30 - 70 °C for 0.1 - 12 h, after washing with water, it is dried at 40 - 80 °C to obtain cross-linked cellulose. The cross-linked cellulose and an aqueous solution of N-methylmorpholine-N-oxide are stirred and dissolved in a reaction kettle under vacuum conditions at 90 - 110 °C for 3 - 5 h to prepare a uniform and transparent spinning solution with a cross-linked cellulose mass fraction of 6 - 10%, and antigen fibrillated fibers are prepared through spinning.

2. The preparation method of an antigen fibrillated cellulose fiber according to claim 1, characterized in that, After the cellulose is impregnated in the finishing solution, ultrasonic treatment is carried out for 12 - 18 min.

3. The preparation method of an antigen fibrillated cellulose fiber according to claim 2, characterized in that, The mass percentage of N-methylmorpholine-N-oxide in the aqueous solution of N-methylmorpholine-N-oxide is 85 - 88%.

4. The preparation method of an antigen fibrillated cellulose fiber according to claim 3, characterized in that, Spinning is carried out by dry-jet wet spinning, and after coagulation in a coagulation bath, washing with water, and drying, antigen fibrillated fibers are obtained, wherein the coagulation bath uses an aqueous solution of an aqueous solution of N-methylmorpholine-N-oxide with a mass fraction of 15 - 20%.

5. The preparation method of an antigen fibrillated cellulose fiber according to claim 4, characterized in that, The pH value of the said finishing solution is adjusted by sodium hydroxide.

6. The preparation method of an antigen fibrillated cellulose fiber according to claim 5, characterized in that, The molecular weight of the said polyaspartic acid is 1000 - 5000 Da.

7. The preparation method of an antigen fibrillated cellulose fiber according to claim 6, characterized in that, The said cellulose is bagasse cellulose or poplar cellulose.

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